Mr Mulhall is reported to have said procedurally it would have been better to have the referendum in October, but French plans to develop EU defence policy during the French presidency later this year would have complicated the referendum campaign.

The memo says French President Nicolas Sarkozy is too unpredictable. Diplomatically that is the most damaging thing in the memo as Ireland is traditionally close to the French particularly on agriculture issues.

That was the main topic when the Taoiseach met President Sarkozy last September in Paris the same day that agreement was struck to send Irish troops to Chad with the French.

The memo also said that other EU partners, especially the commission were being helpful in suppressing news that might affect the referendum campaign.

It said Commission Vice President Margot Wallstrom had told Minister for Foreign Affairs Dermot Ahern they would delay or tone down unhelpful announcements.

The commission has denied that Ms Wallstrom said this.However at least one big announcement, plans for a consolidated corporate tax base, have been put off until the autumn at the request of the Irish.

A spokesman for the British Foreign Office today said that they had a policy of not commenting on leaked documents, but the spokesman did not deny that the contents of the e-mail were accurate.

The memo was leaked to the Daily Mail newspaper in London, but was reprinted in full in The Irish Times.